Anemia in cats occurs when there aren't enough healthy red blood cells to carry oxygen to their body's tissues, making the cat tired and weak. There are two main causes of anemia in cats: Either they don't make enough red blood cells or something is destroying red blood cells faster than they can replace them.

Anemia can be a temporary, one-time problem, or it can be a long-term condition. Further, anemia can range from mild with no noticeable clinical signs to severe enough to be life-threatening. Because of this, cat anemia treatment varies depending on the severity and cause. Let's take a closer look as to what causes a cat to be anemic.

What Causes Anemia in Cats?

While red blood cells play a large role in diagnosing anemic cats, other causes may include the following:

  • Internal or external parasites: A very common cause of anemia in kittens and feral cats, parasites like fleas or roundworms can suck enough blood out of a cat to cause anemia.
  • Infectious diseases: Blood-borne parasites, including Mycoplasma and Cytauxzoon felis, can cause hemolytic anemia (destruction of red blood cells). Anemia is also associated with feline leukemia and feline immunodeficiency virus.
  • Exposure to toxins: Cat-toxic foods, like garlic and onions, can cause anemia. Believe it or not, zinc from pennies minted after 1982, copper toxicosis, moth balls, skunk musk and ibuprofen can all cause hemolytic anemia.
  • Autoimmune disease: Autoimmune anemia occurs when the cat's own immune system attacks and destroys red blood cells. Infectious causes, like the ones already mentioned, trigger autoimmune anemia. In addition, chronic bacterial infections, cancer, some medications, vaccine reactions and hormonal changes are also suspected to cause autoimmune anemia in some cats.
  • Trauma: Hemorrhage from trauma, such as being hit by a car or bit by a dog, can cause life-threatening anemia if not treated immediately.
  • Anemia of chronic disease: Conditions like liver disease, kidney disease, hormonal conditions or cancer can create chronic conditions in the body that reduce the body's ability to create new blood cells, causing non-regenerative anemia.
  • Bone Marrow Damage: A wide variety of toxins, infectious diseases and cancers can result in damage to or the complete destruction of the bone marrow, which produces red blood cells. While sometimes this damage can be corrected if caught early, many times the damage is irreversible and healthy bone marrow is replaced by scar tissue.
  • Inherited disorders: Feline congenital porphyria, a problem stemming from an enzyme deficiency, leads to hemolytic anemia and is a problem mostly seen in the Siamese cat breed.
  • Nutritional deficiency: Anemia can occur in cats that do not get enough iron or cobalamin (vitamin B12).

What Are the Clinical Signs?

Anemic cats may show some of the following clinical signs:

  • Exhaustion
  • Lack of energy
  • Loss of appetite
  • Pale or yellow gums and skin
  • Sensitivity to coldness

If a cat has a primary disease that is causing anemia, such as liver disease, kidney disease or cancer, then they may also show signs associated with those diseases.

How Is Anemia in Cats Diagnosed?

Anemia in cats is diagnosed with a combination of physical examination findings and laboratory testing. Anemia is detected on a blood test called a complete blood count, which does just that: counts all the blood cells. Anemia can also be detected on a blood smear, and if there are any parasites or other red blood cell defects causing the destruction of red blood cells, those can be seen as well. Baby blood cells can also be seen on a blood smear, telling a veterinarian or a pathologist whether or not the cat is making new blood cells.

Because anemia in cats is a secondary problem, it's also necessary to run tests to determine what is causing the anemia. These tests can include any or all of the following: blood work, testing for infectious disease, urine tests, X-rays or other imaging studies, biopsy of abnormal organs or tumors, and more. Each case is unique, and your vet will be your best guide on what tests need to be run.

What Is Cat Anemia Treatment?

As noted above, cat anemia treatment depends on the severity and cause of the anemia. If the anemia is mild to moderate, and the cat shows signs of making new blood cells, it is likely that no treatment will be needed.

Treatment of anemia usually revolves around treating the root cause, which — when healed — allows the cat to heal the anemia (grow new blood cells) on its own. In some cases, such as certain autoimmune diseases or anemia due to chronic kidney problems, there is no cure to the root problem. Treatment in these cases is aimed at reducing the cat's body's autoimmune attack on their own blood cells with immunosuppressive drugs or minimizing the build-up of toxins in the blood in the case of chronic kidney problems.

If the anemia is severe enough to be life-threatening, then your cat may need to have a blood transfusion. Your vet will utilize the results from lab testing, in addition to how your cat is behaving, to determine whether a blood transfusion is necessary or not.

How Can You Prevent Anemia in Cats?

There are many ways you can protect your cat from things that cause anemia. Keeping your cat indoors or taking your cat outside only for supervised fun will help protect your cat from trauma and infectious disease. If your cat does spend time outside, staying up-to-date on external and internal parasite prevention like flea control and regular deworming will keep anemia-causing parasites away. Knowing what toxins cause anemia in cats and barring your cat access to those toxins is also important, as well as visiting your vet yearly to catch any anemia-causing disease processes early to ensure a better outcome.

While anemia may be life-threatening, there are many things you can do to minimize your cat's risk of anemia. All in all, cats are tough creatures, and with a little care from you and your veterinary team, they often recover and live full lives even after having a bout of anemia.

Dr. Sarah Wooten Dr. Sarah Wooten

Dr. Sarah Wooten graduated from UC Davis School of Veterinary Medicine in 2002. A member of the American Society of Veterinary Journalists, Dr. Wooten divides her professional time between small animal practice in Greeley, Colorado, public speaking on associate issues, leadership, and client communication, and writing. She enjoys camping with her family, skiing, SCUBA, and participating in triathlons.

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